The present invention relates to a relatively large aperture telescopic or telephoto type lens system having a viewing angle of about .+-.6.degree. and an aperture ratio of about 1:3.5, composed of four lenses grouped into four components.
A conventional Ernostar type lens system having a large aperture has been provided as a four lens-four group lens construction; however, the aberration, astigmatism and distortion compensation are unsatisfactory in some respects.